In post I’m going to cover Octopus Tentacle automated deployment and registration.
Recently I had situation where I had to install and then register Octopus Tentacles in Azure using ARM templates. The Octopus server was only reachable via public internet using it’s DNS name, by default Octopus will register using the local hostname which wouldn’t work in this case. I couldn’t find a complete example that did exactly what I needed, I’m posting the solution I came up with in case it is needed again.
There is some guidance here around ARM it but it doesn’t cover ARM templates only PowerShell scripts. I took this example anyway and modified it to be a DSC extension in my ARM template and it kind of worked. You can only use one instance of the DSC extension in a template since ARM will try to install it multiple times if you have multiple instances. I needed multiple instances and it failed. I uploaded the ARM example to GitHub anyway if someone needs it for Octopus servers installed in Azure.
In the end I used Azure Custom Script extensions to execute a PowerShell script for the installation. To create the PowerShell script I tried to follow the examples here using Tentacle.exe but still had the problem with the wrong tentacle URL. Using the Octopus.Client dll which was also part of the example didn’t work either, it didn’t configure the Windows service and it assumed you knew the tentacle client thumbprint which you don’t since this is a new installation and the tentacle will generate new thumbprint. Eventually I got it working using a combination of the two and some extra code to retrieve the tentacle client thumbprint. The full sample is here but I will highlight the important parts.
To retrieve the tentacle client thumbprint run:
$raw = .\Tentacle.exe show-thumbprint --nologo --console $client_thumbprint = $raw -Replace 'The thumbprint of this Tentacle is: ', ''
It will print the thumbprint to screen with some extra text you don’t need so I remove the first part.
Secondly don’t call the register-with command shown in the Tentacle.exe example since it will be done using the Octopus.Client dll.
To add multiple roles you have to add them one at a time, to achieve this I pass the roles string to PowerShell as a comma separated value.
"Web Server, Database Server"
And then I split it into an array and loop through it:
foreach($role in (New-Object -TypeName System.String -ArgumentList $roles).Split(','))
{
$tentacle.Roles.Add($role)
}After it is all done you will end up with a new machine in the desired environment with the correct URL.
